Search results for: Mixed Frequency Excitation of an Electrostatically Actuated Resonator
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 2533

Search results for: Mixed Frequency Excitation of an Electrostatically Actuated Resonator

2203 X-Ray Intensity Measurement Using Frequency Output Sensor for Computed Tomography

Authors: R. M. Siddiqui, D. Z. Moghaddam, T. R. Turlapati, S. H. Khan, I. Ul Ahad

Abstract:

Quality of 2D and 3D cross-sectional images produce by Computed Tomography primarily depend upon the degree of precision of primary and secondary X-Ray intensity detection. Traditional method of primary intensity detection is apt to errors. Recently the X-Ray intensity measurement system along with smart X-Ray sensors is developed by our group which is able to detect primary X-Ray intensity unerringly. In this study a new smart X-Ray sensor is developed using Light-to-Frequency converter TSL230 from Texas Instruments which has numerous advantages in terms of noiseless data acquisition and transmission. TSL230 construction is based on a silicon photodiode which converts incoming X-Ray radiation into the proportional current signal. A current to frequency converter is attached to this photodiode on a single monolithic CMOS integrated circuit which provides proportional frequency count to incoming current signal in the form of the pulse train. The frequency count is delivered to the center of PICDEM FS USB board with PIC18F4550 microcontroller mounted on it. With highly compact electronic hardware, this Demo Board efficiently read the smart sensor output data. The frequency output approaches overcome nonlinear behavior of sensors with analog output thus un-attenuated X-Ray intensities could be measured precisely and better normalization could be acquired in order to attain high resolution.

Keywords: Computed tomography, detector technology, X-Ray intensity measurement

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2202 Perception of the Frequency and Importance of Peer Social Support by Students with Special Educational Needs in Inclusive Education

Authors: Lucia Hrebeňárová, Jarmila Žolnová, Veronika Palková

Abstract:

Inclusive education of students with special educational needs has been on the increase in the Slovak Republic, facing many challenges. Preparedness of teachers for inclusive education is one of the most frequent issues; teachers lack skills when it comes to the use of effective instruction depending on the individual needs of students, improvement of classroom management and social skills, and support of inclusion within the classroom. Social support is crucial for the school success of students within inclusive settings. The aim of the paper is to analyse perception of the frequency and importance of peer social support by students with special educational needs in inclusive education. The data collection tool used was the Child and Adolescent Social Support Scale (CASSS). The research sample consisted of 953 fourth grade students – 141 students with special educational needs educated in an inclusive setting and 812 students of the standard population. No significant differences were found between the students with special educational needs and the students without special educational needs in an inclusive setting when it comes to the perception of frequency and importance of social support of schoolmates and friends. However, the perception of frequency and importance of a friend’s social support was higher than the perception of frequency and importance of a classmate’s social support in both groups of students.

Keywords: Inclusive education, peer social support, peer, student with special educational needs.

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2201 Development of a Comprehensive Electricity Generation Simulation Model Using a Mixed Integer Programming Approach

Authors: Erik Delarue, David Bekaert, Ronnie Belmans, William D'haeseleer

Abstract:

This paper presents the development of an electricity simulation model taking into account electrical network constraints, applied on the Belgian power system. The base of the model is optimizing an extensive Unit Commitment (UC) problem through the use of Mixed Integer Linear Programming (MILP). Electrical constraints are incorporated through the implementation of a DC load flow. The model encloses the Belgian power system in a 220 – 380 kV high voltage network (i.e., 93 power plants and 106 nodes). The model features the use of pumping storage facilities as well as the inclusion of spinning reserves in a single optimization process. Solution times of the model stay below reasonable values.

Keywords: Electricity generation modeling, Unit Commitment(UC), Mixed Integer Linear Programming (MILP), DC load flow.

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2200 Simulation-Based Optimization of a Non-Uniform Piezoelectric Energy Harvester with Stack Boundary

Authors: Alireza Keshmiri, Shahriar Bagheri, Nan Wu

Abstract:

This research presents an analytical model for the development of an energy harvester with piezoelectric rings stacked at the boundary of the structure based on the Adomian decomposition method. The model is applied to geometrically non-uniform beams to derive the steady-state dynamic response of the structure subjected to base motion excitation and efficiently harvest the subsequent vibrational energy. The in-plane polarization of the piezoelectric rings is employed to enhance the electrical power output. A parametric study for the proposed energy harvester with various design parameters is done to prepare the dataset required for optimization. Finally, simulation-based optimization technique helps to find the optimum structural design with maximum efficiency. To solve the optimization problem, an artificial neural network is first trained to replace the simulation model, and then, a genetic algorithm is employed to find the optimized design variables. Higher geometrical non-uniformity and length of the beam lowers the structure natural frequency and generates a larger power output.

Keywords: Piezoelectricity, energy harvesting, simulation-based optimization, artificial neural network, genetic algorithm.

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2199 Development of an Efficient CVT using Electromecanical System

Authors: A. A. Shafie, M. H. Ali

Abstract:

Continuously variable transmission (CVT) is a type of automatic transmission that can change the gear ratio to any arbitrary setting within the limits. The most common type of CVT operates on a pulley system that allows an infinite variability between highest and lowest gears with no discrete steps. However, the current CVT system with hydraulic actuation method suffers from the power loss. It needs continuous force for the pulley to clamp the belt and hold the torque resulting in large amount of energy consumption. This study focused on the development of an electromechanical actuated control CVT to eliminate the problem that faced by the existing CVT. It is conducted with several steps; computing and selecting the appropriate sizing for stroke length, lead screw system and etc. From the visual observation it was found that the CVT system of this research is satisfactory.

Keywords: CVT, Hydraulic Actuator, Discrete shifts, Electromechanical system, Lead screws.

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2198 A Cognitive Model for Frequency Signal Classification

Authors: Rui Antunes, Fernando V. Coito

Abstract:

This article presents the development of a neural network cognitive model for the classification and detection of different frequency signals. The basic structure of the implemented neural network was inspired on the perception process that humans generally make in order to visually distinguish between high and low frequency signals. It is based on the dynamic neural network concept, with delays. A special two-layer feedforward neural net structure was successfully implemented, trained and validated, to achieve minimum target error. Training confirmed that this neural net structure descents and converges to a human perception classification solution, even when far away from the target.

Keywords: Neural Networks, Signal Classification, Adaptative Filters, Cognitive Neuroscience

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2197 Identification of Impact of Electromagnetic Fields at Low and High Frequency on Human Body

Authors: P. Sowa

Abstract:

The article reviews the current state of large-scale studies about the impact of electromagnetic field on natural environment. The scenario of investigations – simulation of natural conditions at the workplace, taking into consideration the influence both low and high frequency electromagnetic fields is shown.The biological effects of low and high frequency electromagnetic fields are below presented. Results of investigation with animals are shown. The norms and regulations concerning the levels of electromagnetic field intensity are reviewed.

Keywords: Electromagnetic field and environment, biological effects of electric field on human body, simulation of natural condition at workplace

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2196 Design of SiC Capacitive Pressure Sensor with LC-Based Oscillator Readout Circuit

Authors: Azza M. Anis, M. M. Abutaleb, Hani F. Ragai, M. I. Eladawy

Abstract:

This paper presents the characterization and design of a capacitive pressure sensor with LC-based 0.35 µm CMOS readout circuit. SPICE is employed to evaluate the characteristics of the readout circuit and COMSOL multiphysics structural analysis is used to simulate the behavior of the pressure sensor. The readout circuit converts the capacitance variation of the pressure sensor into the frequency output. Simulation results show that the proposed pressure sensor has output frequency from 2.50 to 2.28 GHz in a pressure range from 0.1 to 2 MPa almost linearly. The sensitivity of the frequency shift with respect to the applied pressure load is 0.11 GHz/MPa.

Keywords: CMOS LC-based oscillator, micro pressure sensor, silicon carbide

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2195 Low Frequency Noise Behavior of Independent Gate Junctionless FinFET

Authors: A. Kamath, Z. X. Chen, C. J. Gu, F. Zheng, X. P. Wang, N. Singh, G-Q. Lo

Abstract:

In this paper we use low frequency noise analysis to understand and map the current conduction path in a multi gate junctionless FinFET.  The device used in this study behaves as a gated resistor and shows excellent short channel effect suppression due to its multi gate structure. Generally for a bulk conduction device like the junctionless device studied in this work, the low frequency noise can be modelled using the mobility fluctuation model; however for this device we can also see the effect of carrier fluctuations on the LFN characteristic. The noise characteristic at different gate bias and also the possible location of the traps is explained.

Keywords: LFN analysis, junctionless, Current conduction path, FinFET.

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2194 Liquid Crystal Based Reconfigurable Reflectarray Antenna Design

Authors: M. Y. Ismail, M. Inam

Abstract:

This paper presents the design and analysis of Liquid Crystal (LC) based tunable reflectarray antenna with slot embedded patch element configurations within X-band frequency range. The slots are shown to modify the surface current distribution on the patch element of reflectarray which causes the resonant patch element to provide different resonant frequencies depending on the slot dimensions. The simulated results are supported and verified by waveguide scattering parameter measurements of different reflectarray unit cells. Different rectangular slots on patch element have been fabricated and a change in resonant frequency from 10.46GHz to 8.78GHz has been demonstrated as the width of the rectangular slot is varied from 0.2W to 0.6W. The rectangular slot in the center of the patch element has also been utilized for the frequency tunable reflectarray antenna design based on K-15 Nematic LC. For the active reflectarray antenna design, a frequency tunability of 1.2% from 10GHz to 9.88GHz has been demonstrated with a dynamic phase range of 103° provided by the measured scattering parameter results. Time consumed by liquid crystals for reconfiguration, which is one of the drawback of LC based design, has also been disused in this paper.

Keywords: Liquid crystal, tunable reflectarray, frequency tunability, dynamic phase range.

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2193 Optimal Production Planning in Aromatic Coconuts Supply Chain Based On Mixed-Integer Linear Programming

Authors: Chaimongkol Limpianchob

Abstract:

This work addresses the problem of production planning that arises in the production of aromatic coconuts from Samudsakhorn province in Thailand. The planning involves the forwarding of aromatic coconuts from the harvest areas to the factory, which is classified into two groups; self-owned areas and contracted areas, the decisions of aromatic coconuts flow in the plant, and addressing a question of which warehouse will be in use. The problem is formulated as a mixed-integer linear programming model within supply chain management framework. The objective function seeks to minimize the total cost including the harvesting, labor and inventory costs. Constraints on the system include the production activities in the company and demand requirements. Numerical results are presented to demonstrate the feasibility of coconuts supply chain model compared with base case.

Keywords: Aromatic coconut, supply chain management, production planning, mixed-integer linear programming.

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2192 Fast Object/Face Detection Using Neural Networks and Fast Fourier Transform

Authors: Hazem M. El-Bakry, Qiangfu Zhao

Abstract:

Recently, fast neural networks for object/face detection were presented in [1-3]. The speed up factor of these networks relies on performing cross correlation in the frequency domain between the input image and the weights of the hidden layer. But, these equations given in [1-3] for conventional and fast neural networks are not valid for many reasons presented here. In this paper, correct equations for cross correlation in the spatial and frequency domains are presented. Furthermore, correct formulas for the number of computation steps required by conventional and fast neural networks given in [1-3] are introduced. A new formula for the speed up ratio is established. Also, corrections for the equations of fast multi scale object/face detection are given. Moreover, commutative cross correlation is achieved. Simulation results show that sub-image detection based on cross correlation in the frequency domain is faster than classical neural networks.

Keywords: Conventional Neural Networks, Fast Neural Networks, Cross Correlation in the Frequency Domain.

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2191 Spatial Time Series Models for Rice and Cassava Yields Based On Bayesian Linear Mixed Models

Authors: Panudet Saengseedam, Nanthachai Kantanantha

Abstract:

This paper proposes a linear mixed model (LMM) with spatial effects to forecast rice and cassava yields in Thailand at the same time. A multivariate conditional autoregressive (MCAR) model is assumed to present the spatial effects. A Bayesian method is used for parameter estimation via Gibbs sampling Markov Chain Monte Carlo (MCMC). The model is applied to the rice and cassava yields monthly data which have been extracted from the Office of Agricultural Economics, Ministry of Agriculture and Cooperatives of Thailand. The results show that the proposed model has better performance in most provinces in both fitting part and validation part compared to the simple exponential smoothing and conditional auto regressive models (CAR) from our previous study.

Keywords: Bayesian method, Linear mixed model, Multivariate conditional autoregressive model, Spatial time series.

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2190 A Research about Determination of the Quality of Feed Oils Used as Mixed Feed Raw Material from Some Feed Factories in Konya-Turkey

Authors: Gülşah Kanbur, Veysel Ayhan

Abstract:

Feed oil samples which are used as mixed feed raw material were taken from six different feed factories in March, May and July. All factories make production in Konya, Turkey and all of the samples were crude soybean oils. Physical and chemical analyses, free radical scavenger effect, and total phenol content were determined on these oil samples. Moisture (M) content was found between 0.10-22.23%, saponification number (SF) was determined 143.13 to 167.93 KOH/kg, free fatty acidity (FFA) was varied 0.73 to 35.00%, peroxide value (PV) was found between 1.53 and 28.43 meq/kg, unsaponifiable matter (USM) was determined from 0.40 to 17.10%, viscosity (V) was found between 34.30 and 625.67 mPas, sediment (S) amount was determined between 0.60-18.16%, free radical scavenger effect (FRSE) was varied 20.7 to 43.04% inhibition of the extract and total phenol (TPC) content was found between 1.20 and 2.69mg/L extract. Different results were found between months and factories.

Keywords: Crude soybean oil, Feed oils, mixed feed.

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2189 Theoretical Investigation on the Dynamic Characteristics of One Degree of Freedom Vibration System Equipped with Inerter of Variable Inertance

Authors: Barenten Suciu, Yoshiki Tsuji

Abstract:

In this paper, a theoretical investigation on the dynamic characteristics of one degree of freedom vibration system equipped with inerter of variable inertance, is presented. Differential equation of movement was solved under proper initial conditions in the case of free undamped/damped vibration, considered in the absence/presence of the inerter in the mechanical system. Influence of inertance on the amplitude of vibration, phase angle, natural frequency, damping ratio, and logarithmic decrement was clarified. It was mainly found that the inerter decreases the natural frequency of the undamped system and also of the damped system if the damping ratio is below 0.707. On the other hand, the inerter increases the natural frequency of the damped system if the damping ratio exceeds 0.707. Results obtained in this work are useful for the adequate design of inerters.

Keywords: One degree of freedom vibration system, inerter, parallel connection, variable inertance, frequency control, damping.

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2188 Multi-Focus Image Fusion Using SFM and Wavelet Packet

Authors: Somkait Udomhunsakul

Abstract:

In this paper, a multi-focus image fusion method using Spatial Frequency Measurements (SFM) and Wavelet Packet was proposed. The proposed fusion approach, firstly, the two fused images were transformed and decomposed into sixteen subbands using Wavelet packet. Next, each subband was partitioned into sub-blocks and each block was identified the clearer regions by using the Spatial Frequency Measurement (SFM). Finally, the recovered fused image was reconstructed by performing the Inverse Wavelet Transform. From the experimental results, it was found that the proposed method outperformed the traditional SFM based methods in terms of objective and subjective assessments.

Keywords: Multi-focus image fusion, Wavelet Packet, Spatial Frequency Measurement.

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2187 Extraction of Fetal Heart Rate and Fetal Heart Rate Variability from Mother's ECG Signal

Authors: Khaldon Lweesy, Luay Fraiwan, Christoph Maier, Hartmut Dickhaus

Abstract:

This paper describes a new method for extracting the fetal heart rate (fHR) and the fetal heart rate variability (fHRV) signal non-invasively using abdominal maternal electrocardiogram (mECG) recordings. The extraction is based on the fundamental frequency (Fourier-s) theorem. The fundamental frequency of the mother-s electrocardiogram signal (fo-m) is calculated directly from the abdominal signal. The heart rate of the fetus is usually higher than that of the mother; as a result, the fundamental frequency of the fetal-s electrocardiogram signal (fo-f) is higher than that of the mother-s (fo-f > fo-m). Notch filters to suppress mother-s higher harmonics were designed; then a bandpass filter to target fo-f and reject fo-m is implemented. Although the bandpass filter will pass some other frequencies (harmonics), we have shown in this study that those harmonics are actually carried on fo-f, and thus have no impact on the evaluation of the beat-to-beat changes (RR intervals). The oscillations of the time-domain extracted signal represent the RR intervals. We have also shown in this study that zero-to-zero evaluation of the periods is more accurate than the peak-to-peak evaluation. This method is evaluated both on simulated signals and on different abdominal recordings obtained at different gestational ages.

Keywords: Aabdominal ECG, fetal heart rate variability, frequency harmonics, fundamental frequency.

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2186 Visitors’ Attitude towards the Service Marketing Mix and Frequency of Visits to Bangpu Recreation Centre, Thailand

Authors: Siri-Orn Champatong

Abstract:

This research paper was aimed to examine the relationship between visitors’ attitude towards the service marketing mix and visitors’ frequency of visit to Bangpu Recreation Centre. Based on a large and uncalculated population, the number of samples was calculated according to the formula to obtain a total of 385 samples. In collecting the samples, systematic random sampling was applied and by using of a Likert five-scale questionnaire for, a total of 21 days to collect the needed information. Mean, Standard Deviation, and Pearson’s basic statistical correlations were utilized in analyzing the data. This study discovered a high level of visitors’ attitude product and service of Bangpu Recreation Centre, price, place, promotional activities, people who provided service and physical evidence of the centre. The attitude towards process of service was discovered to be at a medium level. Additionally, the finding of an examination of a relationship between visitors’ attitude towards service marketing mix and visitors’ frequency of visit to Bangpu Recreation Centre presented that product and service, people, physical evidence and process of service provision showed a relationship with the visitors’ frequency of visit to the centre per year.

Keywords: Frequency of Visit, Visitor, Service Marketing Mix, Bangpu Recreation Centre.

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2185 Ultra Wideband Breast Cancer Detection by Using SAR for Indication the Tumor Location

Authors: Wittawat Wasusathien, Samran Santalunai, Thanaset Thosdeekoraphat, Chanchai Thongsopa

Abstract:

This paper presents breast cancer detection by observing the specific absorption rate (SAR) intensity for identification tumor location, the tumor is identified in coordinates (x,y,z) system. We examined the frequency between 4-8 GHz to look for the most appropriate frequency. Results are simulated in frequency 4-8 GHz, the model overview include normal breast with 50 mm radian, 5 mm diameter of tumor, and ultra wideband (UWB) bowtie antenna. The models are created and simulated in CST Microwave Studio. For this simulation, we changed antenna to 5 location around the breast, the tumor can be detected when an antenna is close to the tumor location, which the coordinate of maximum SAR is approximated the tumor location. For reliable, we experiment by random tumor location to 3 position in the same size of tumor and simulation the result again by varying the antenna position in 5 position again, and it also detectable the tumor position from the antenna that nearby tumor position by maximum value of SAR, which it can be detected the tumor with precision in all frequency between 4-8 GHz.

Keywords: Specific absorption rate (SAR), ultra wideband (UWB), coordinates and cancer detection

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2184 Novel Sinusoidal Pulse Width Modulation with Least Correlated Noise

Authors: Shiang-Hwua Yu, Han-Sheng Tseng

Abstract:

This paper presents a novel sinusoidal modulation scheme that features least correlated noise and high linearity. The modulation circuit, which is composed of a quantizer, a resonator, and a comparator, is capable of eliminating correlated modulation noise while doing modulation. The proposed modulation scheme combined with the linear quadratic optimal control is applied to a single-phase voltage source inverter and validated with the experiment results. The experiments show that the inverter supplies stable 60Hz 110V AC power with a total harmonic distortion of less than 1%, under the DC input variation from 190 V to 300 V and the output power variation from 0 to 600 W.

Keywords: Pulse width modulation, feedback dithering, linear quadratic control, inverter.

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2183 Tuning a Fractional Order PID Controller with Lead Compensator in Frequency Domain

Authors: Tahmine. V. Moghaddam, N. Bigdeli, K. Afshar

Abstract:

To achieve the desired specifications of gain and phase margins for plants with time-delay that stabilized with FO-PID controller a lead compensator is designed. At first the range of controlled system stability based on stability boundary criteria is determined. Using stability boundary locus method in frequency domain the fractional order controller parameters are tuned and then with drawing bode diagram in frequency domain accessing to desired gain and phase margin are shown. Numerical examples are given to illustrate the shapes of the stabilizing region and to show the design procedure.

Keywords: Fractional controller, Lead compensator, Stabilityregions, Stability boundary locus

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2182 Frequency- and Content-Based Tag Cloud Font Distribution Algorithm

Authors: Ágnes Bogárdi-Mészöly, Takeshi Hashimoto, Shohei Yokoyama, Hiroshi Ishikawa

Abstract:

The spread of Web 2.0 has caused user-generated content explosion. Users can tag resources to describe and organize them. Tag clouds provide rough impression of relative importance of each tag within overall cloud in order to facilitate browsing among numerous tags and resources. The goal of our paper is to enrich visualization of tag clouds. A font distribution algorithm has been proposed to calculate a novel metric based on frequency and content, and to classify among classes from this metric based on power law distribution and percentages. The suggested algorithm has been validated and verified on the tag cloud of a real-world thesis portal.

Keywords: Tag cloud, font distribution algorithm, frequency-based, content-based, power law.

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2181 Advancing the Theory of Planned Behavior within Dietary and Physical Domains among Type 2 Diabetics: A Mixed Methods Approach

Authors: D.O. Omondi, M.K. Walingo, G.M. Mbagaya, L.O.A. Othuon

Abstract:

Many studies have applied the Theory of Planned Behavior (TPB) in predicting health behaviors among unique populations. However, a new paradigm is emerging where focus is now directed to modification and expansion of the TPB model rather than utilization of the traditional theory. This review proposes new models modified from the Theory of Planned Behavior and suggest an appropriate study design that can be used to test the models within physical activity and dietary practice domains among Type 2 diabetics in Kenya. The review was conducted by means of literature search in the field of nutrition behavior, health psychology and mixed methods using predetermined key words. The results identify pre-intention and post intention gaps within the TPB model that need to be filled. Additional psychosocial factors are proposed to be included in the TPB model to generate new models and the efficacy of these models tested using mixed methods design.

Keywords: Physical activity, diet, Type 2 diabetes, behaviorchange theory, model.

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2180 A Case Study of Limited Dynamic Voltage Frequency Scaling in Low-Power Processors

Authors: Hwan Su Jung, Ahn Jun Gil, Jong Tae Kim

Abstract:

Power management techniques are necessary to save power in the microprocessor. By changing the frequency and/or operating voltage of processor, DVFS can control power consumption. In this paper, we perform a case study to find optimal power state transition for DVFS. We propose the equation to find the optimal ratio between executions of states while taking into account the deadline of processing time and the power state transition delay overhead. The experiment is performed on the Cortex-M4 processor, and average 6.5% power saving is observed when DVFS is applied under the deadline condition.

Keywords: Deadline, Dynamic Voltage Frequency Scaling, Power State Transition.

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2179 Main Variables Competition in DFB Lasers under Dual Optical Injection

Authors: Najm M. Al-Hosiny

Abstract:

We theoretically investigate the effects of frequency detuning and injection power on the nonlinear dynamics of DFB lasers under dual external optical injection.

Keywords: Optical injection, DFB laser, frequency detuning, injection power.

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2178 Performance Evaluation of a Neural Network based General Purpose Space Vector Modulator

Authors: A.Muthuramalingam, S.Himavathi

Abstract:

Space Vector Modulation (SVM) is an optimum Pulse Width Modulation (PWM) technique for an inverter used in a variable frequency drive applications. It is computationally rigorous and hence limits the inverter switching frequency. Increase in switching frequency can be achieved using Neural Network (NN) based SVM, implemented on application specific chips. This paper proposes a neural network based SVM technique for a Voltage Source Inverter (VSI). The network proposed is independent of switching frequency. Different architectures are investigated keeping the total number of neurons constant. The performance of the inverter is compared for various switching frequencies for different architectures of NN based SVM. From the results obtained, the network with minimum resource and appropriate word length is identified. The bit precision required for this application is identified. The network with 8-bit precision is implemented in the IC XCV 400 and the results are presented. The performance of NN based general purpose SVM with higher bit precision is discussed.

Keywords: NN based SVM, FPGA Implementation, LayerMultiplexing, NN structure and Resource Reduction, PerformanceEvaluation

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2177 ESS Control Strategy for Primary Frequency Response in Microgrid Considering Ramp Rate

Authors: Ho-Jun Jo, Wook-Won Kim, Yong-Sung Kim, Jin-O Kim

Abstract:

The application of ESS (Energy Storage Systems) in the future grids has been the solution of the microgrid. However, high investment costs necessitate accurate modeling and control strategy of ESS to justify its economic viability and further underutilization. Therefore, the reasonable control strategy for ESS which is subjected to generator and usage helps to curtail the cost of investment and operation costs. The rated frequency in power system is decreased when the load is increasing unexpectedly; hence the thermal power is operated at the capacity of only its 95% for the Governor Free (GF) to adjust the frequency as reserve (5%) in practice. The ESS can be utilized with governor at the same time for the frequency response due to characteristic of its fast response speed and moreover, the cost of ESS is declined rapidly to the reasonable price. This paper presents the ESS control strategy to extend usage of the ESS taken account into governor’s ramp rate and reduce the governor’s intervention as well. All results in this paper are simulated by MATLAB.

Keywords: Micro grid, energy storage systems, ramp rate, control strategy.

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2176 An Improved Integer Frequency Offset Estimator using the P1 Symbol for OFDM System

Authors: Yong-An Jung, Young-Hwan You

Abstract:

This paper suggests an improved integer frequency offset (IFO) estimation scheme using P1 symbol for orthogonal frequency division multiplexing (OFDM) based the second generation terrestrial digital video broadcasting (DVB-T2) system. Proposed IFO estimator is designed by a low-complexity blind IFO estimation scheme, which is implemented with complex additions. Also, we propose active carriers (ACs) selection scheme in order to prevent performance degradation in blind IFO estimation. The simulation results show that under the AWGN and TU6 channels, the proposed method has low complexity than conventional method and almost similar performance in comparison with the conventional method.

Keywords: OFDM, DVB-T2, P1 symbol, ACs, IFO.

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2175 Pulse Skipping Modulated DC to DC Step Down Converter Under Discontinuous Conduction Mode

Authors: Ramamurthy S, Ranjan P V, Raghavendiran T A

Abstract:

Reduced switching loss favours Pulse Skipping Modulation mode of switching dc-to-dc converters at light loads. Under certain conditions the converter operates in discontinuous conduction mode (DCM). Inductor current starts from zero in each switching cycle as the switching frequency is constant and not adequately high. A DC-to-DC buck converter is modelled and simulated in this paper under DCM. Effect of ESR of the filter capacitor in input current frequency components is studied. The converter is studied for its operation under input voltage and load variation. The operating frequency is selected to be close to and above audio range.

Keywords: Buck converter, Discontinuous conduction mode, Electromagnetic Interference, Pulse Skipping Modulation.

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2174 Novel Approach for Wideband VNA by Sixport Principle

Authors: Tomáš Urbanec

Abstract:

Paper presents simple sixport principle and its frequency bandwidth. The novel multisixport approach is presented with its possibilities, typical parameters and frequency bandwidth. Practical implementation is shown with its measurement parameters and calibration. The bandwidth circa 1:100 is obtained.

Keywords: microwave measurement, sixport, VNA, wideband.

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